"Construction workers!" The teacher yelped while he turned on a TV in front of me and the other four guys that made our group.
A rather skinny blonde haired guy named Gary raised his hand. "I'm sorry, teacher but I'm not material for the construction world, I'm more interested in using my mind over my muscles."
The teacher grinned while he played a video. "That doesn't matter, Gary! Perhaps you have doubts now but that's why you'll see this video. After watching it you could learn about this job for yourselves. I'm sure you will change your mind through the practical education."
Gary reluctantly agreed to watch the video as well as me and the other three guys. At first it wasn't anything special, just another documentary about construction. However, as time passes it was becoming more and more interesting. Gary and his friends were carefully watching at every detail that it was on screen. I don't want to admit it but I was doing the same, it's like a hypnotic but pleasant effect that was taking our full attention.
We had watched half of the video when I get a phone call from my roommate. "Caleb, I need your help! I left my keys in our room, can you lend me yours? I'm at the entrance." I didn't want to help him but I owe it to him because the same happened to me yesterday and he helped me. I excused to the teacher and ran as fast as I can to my dorm where my roommate was waiting for me. I opened the door and ran back to the classroom hoping the video hasn't ended.
Fortunately, it hasn't. However, my happiness just last a moment because it ended after 3 minutes. The teacher saw my disappointed face and gave me a copy of the video to watch it at my place.
"Just make sure you watch it completely." I nodded and left the classroom to return to my dorm. During my walking I barely noticed that Gary and his friends who were behaving a little strange, almost in trance.
To be honest, at moment I arrived to my dorm I lost my interest on the topic. I threw my video on a corner and didn't touch it until the next day when I had to return it to the teacher. He asked me if I watched it and I told him that I did it. He just grinned and did the same that yesterday, he played another video anout construction workers. However, unlike Gary and his friends I wasn't too interested and it gradually became boring.
After several weeks, the teacher told us that we were ready for the practical lessons. I didn't get it at first, although I felt la different behavior coming from me and my classmates as I pointed out before with the increased libido that I described.
However, what was coming was way more than just horny guys. The teacher asked for two volunteers who will be the first ones to take the practical lessons. I had the idea that who starts first, ends first too, so I volunteered as well as Gary. The teacher grinned and gave us a document to sign, it was a contract where we commit to complete our lessons. It was weird but we signed it. Then everything became blur.
"What happens, teacher?" I heard Gary saying and then I watched the teacher hidden a weird looking machine behind his desk.
"Now class, while Caleb and Gary change you will take note about their process, make sure you watched carefully the before and the after." The boys in the group sat in silence, no one quite knew what to expect.
"What do you mean about change?" Gary asked but he and everyone surprised when we heard a deep voice instead of his regular soprano.
He panicked touched his neck just to find a big lump where there was nothing before. However, that wasn't what freaked him more, the hand that he used to touch it was a big and calloused hand not his feminine one. After that, I stared how were his arms beffing in a matter of seconds. He has the arms of a professional weightlifter despite he has never gone to a gym.
"Caleb, your chest!" Gary shouted at me while he pointed at me with his sausage fingers, "Holy smokes! Me too!!" I looked at him and noticed that hid chest, back and abdomen were broadening and filling in with a ton of muscles, and that's not all because hair was coming out wildy with it. I looked at myself and realized that my fear was right, my chest was now hidden behind a thick rug of hair. Of course, my chest was way more bigger and my hands now had sausage fingers like Gary.
"Isn't it exciting?! You will experience the construction work first-hand!!" The teacher smiled while he clapped our newly broadened backs.
After the first shock, Gary complained to the teacher. "I don't want to change! I didn't ask for th-!" Gary didn't get to finish his thought. He felt a powerful feeling in his groin that was quickly noticeable to the classroom. He instinctively put his hands on his manhood, he could feel odd spasms happening throughout his body.
Before he had a chance to follow up, the room was silence by the powerful sound of your clothes ripping closely followed by Gary's. You immediately turned beet red. "O-oh n-no!! Please, don't watch me!" Gary shouted while he tried to cover the ragging boner that was still growing.
"No need to feel shame, Gary! All those muscles need a strong testosterone source, it's not just increasing your genitals size but your libido too! Don't you feel horny now?"
"Wha?" Gary responded. He was so out of it, his growing need to stroke his was shaft was commanding his attention. He put a hand on his balls and felt them swelling hefty and virile, the aroma of his musk was intoxicating you and you quickly realized that you was having a similar effect on him. Within a moment, Gary released a strong load of cum into his hairy chest, you stared at him while you kept stroking yourself.
"Uuugh, Teacher, what's happening to me?" Gary weakly asked. His body was beginning to feel heavy.
"Now your mind is getting used to your new body. Don't worry, those videos will help you to think like a real construction worker!" The teacher replied. Meanwhile, you was releasing your own seed to the floor. You don't feel anything else was changing and you started to think that your mind wasn't adapting to your body because you don't watch those videos completely.